1. Field of the Invention
The invention relates to the field of measurement and visualization of the superficial surface appearance, three dimensional contour and subsurface structure of an object, and in particular to improvements in orthodontics and oral surgery in measuring and visualizing anatomical landmarks used in orthodontic analysis by direct measurement of the face, head and jaws of a subject to produce correlated video, laser and x-ray derived measured images and to topologically transform the same to hypothetical modifications for visualization.
2. Description of the Prior Art
The apparatus for generating cephalometric tracings directly from a patient by generating digitized two or three dimensional data from a patient's head from defined locations of preselected landmarks is well known and is based on the use of optical or sonic marking using three dimensional triangulation. For example, such an apparatus is shown and described in Lemchen, et al. "Method and Apparatus for Generating Cephalometric Images," U.S. Pat. No. 5,278,756 (1994) in which a means for defining a position with respect to a given anatomical reference is provided by a probe having a tip which generates signals of a certain optical or sonic frequency, when activated when positioned at selected reference points on the head or jaw. Triangulation detectors receive the position indicating signals from the probe and a computer processes the received signals to provide digital data corresponding to the three dimensional location of the probe tip with reference to the head or jaw. A visual image of the head or jaw is displayed as seen from a chosen direction or directions with a video camera. The video image is displayed together with a cephalometric tracing as would be seen in the same direction and scale which tracing is derived by joining appropriate anatomical landmarks with tracing lines generated by the computer according to any one of a number of accepted tracing techniques.
Lateral cephalograms using x-ray exposures are also well known from conventional orthodontic diagnosis. One prior art system for computer generating lateral cephalometric tracings is described in Ricketts, et al., "Orthodontic Diagnosis and Planning" as published by Rocky Mountain Orthodontics of Denver, Colo. (1982).
Panoramic radiography is also well established and has recently been commercialized to create digitized x-ray panographs as, for example, as provided by the system sold under the trademark, Siemens SIDEXIS, as manufactured by Pelton & Crane of Charlotte, N.C. Digitized x-ray signals are received directly from the panographic exposure and real time processing enables immediate display of the x-ray images on a monitor.
However, the panographic gantry and exposure equipment operates solely in connection with a single x-ray exposure and image. The laser optical or sonic equipment described in U.S. Pat. No. 5,278,756 also operates solely in relationship to a single detection and imaging system. The data from the separate x-ray panograph and the optical or sonic cephalometric trace can be downloaded into a single computer and through nontrivial and substantial computing effort with some degree of programming skill, the two sets of data can be correlated after the fact. However, such an approach requires multiple exposure apparatus, and considerable time and computer operator skill in order to obtain usefully correlated x-ray and laser images.
Marks, "Combined Imaging Scanner," U.S. Pat. No. 5,391,877 (1995) describes an image scanner that combines images obtained from two systems that are supported on a combined gantry. The Single Photon Emission Computed Tomographic (SPECT) Scanner includes a gantry supporting a computed tomographic (CT) Scanner 12. The gantry also supports the SPECT Scanner 14. The single table 16 supporting the patient's position sequentially pass through both gantries. Initially the CT data is obtained and then the SPECT data. The single computer 18 mathematically convolves the two image data sets. The CT data is processed to provide a background or map on which to superimpose the SPECT data. As The CT anatomical data is convolved with the SPECT radioisotope distribution data to provide a color-shaded relief image. A single computer 18 is used for the analysis. The information is displayed on a machine control display 20, a raw CT display terminal 22, and a raw SPECT display terminal 24 and a combined CSPECT display terminal 26. Image on the display terminal 26 can be printed to a color laser printer 28.
Wessels, "Alignment System to Overlay Abdominal Computer Aided Tomography and Magnetic Resonance Anatomy With Single Photon Emissions Tomography," U.S. Pat. No. 5,299,253 (1994) describes a system comprised of machine-base support means: (a) with a contrasting marker means (b) attached to the support for providing a set of markings which uniquely identifies a cross-section of an imaged object. The support means includes material encasement, and means to encapsulate the contrasting markers in an inert material. The material for the encasement may be polymer, wood, foam, metal, ceramic or a combination of these materials which do not otherwise interfere with the imaging system. Contrasting marker (b) is a mark whose outline can be accurately viewed without distortion or blurring within the image system being used. The marker can have many shapes including that of a solid or hollow tube. The contrast agent in the marker is a solid, liquid or gas which is readily discernible with a particular type of imaging system used. The pattern of contrast markers must be such that there is at least one transversely constant contrast marker and at least one transversely variable contrast marker spanning the longitudinal and imaging area. The alignment system can be used in one plane, or there can be a series of alignment systems in planes above the object to be imaged. In use, for registering single photon emission tomography images with computer tomography or magnetic resonance images, the object to be imaged placed on a support means. The support means can be a partial cast of the object's external shape. At least a portion of the object is adjacent to a contrast marker means. The object is imaged using two or more imaging techniques. At least two images of the object are registered to produce a coherent image of the object.
Mohr, et al., "System and Method For Using A Dual Modality Detector For Inspecting Objects," U.S. Pat. No. 5,519,225 (1996) describes an industrial inspection system using a dual modality gas ionization detector with beams of either neutrons or photons from X-rays or gamma rays passing through the object. A dual modality gas ionization detector 10 has a window 16 for transmitting X-rays or gamma rays. The windows is made of a material which is permeable to these types of radiation. The detector includes a housing 12 that has an ionization chamber 18 filled with high pressure gases such as helium or Xe, which chamber 18 is used to detect the neutron, x-ray or gamma rays fluxes incident on the ionization detector.
The inspection system is used to detect the presence of nitride and titanium sponge nuggets or residual core material in hollow-cast turbine engine blades. Mohr was cited for showing the simultaneous irradiation of objects with two types of radiation and the simultaneous and alternating detection of the same. The structure of the Mohr device includes a collimator 20 comprised of two bars 22 and 24 define a slit 26 between them which collimates the beams entering the chamber into a thinner beam. The beams entering the chamber interact with gases to produce a secondary-ionization charge that has accelerated toward electrodes 28. A single layer of nuggets 34 on conveyor belt 40 are imaged by moving past a dual radiation source 42, which alternately pulses neutrons and X-rays or gamma rays at the nuggets. The dual modality gas ionization detector 10 measures the transmissivity of the alternating radiation passing through the nuggets and supplies a signal to image generator 46. Image generator 46 includes an analog digital converter 48, processing means 50 and an image display device 52.
Dumoulin, et al., "Stereoscopic X-Ray Fluoroscopy System using Radiofrequency Fields," U.S. Pat. No. 5,251,635 (1993). The system is directed to minimizing an X-ray dose while still providing a stereoscopic tracking image of an invasive device in a patient. FIG. 1 shows a patient 112 positioned in the X-ray imaging system. The system provides a stereoscopic view of the patient with the X-ray image being only occasioned updated. The computer system tracks the invasive device and provides a superimposed image of the evasive device with the position being updated at a high rate. The invasive device has a transmitter coil that transmits an RF signal to a plurality receiving coils placed around the patient. The tracking computer calculates the position and orientation of the invasive device and supplies the image superpositioned on the last X-ray image. The tracking system can be used with other imaging systems such as magnetic resonant scanners, ultra sound scanners, positron emission, tomography scanners and the like.
Suckewer, et al., "X-Ray Laser Microscope Apparatus," U.S. Pat. No. 4,979,203 (1990) describes an X-ray contact microscope and optical phase contrast microscopic system. Object cells 22 have been cultured on an X-ray resist surface 46. An inverted microscope 26 using light source 34 is used to position the object cells for exposure to a soft X-ray beam 30 from an x-ray laser source 200. An ultraviolet light source 66 is provided to monitor fluorescent effects of the object.
None of the prior art references show a multiple scanning exposure system for dental application in which the dental X-ray is separately created and combined with video and laser scanning of a patient's face or jaw structure.
None of the systems are concerned with combinations which would combine surface data, and in particular, facial surface data, with underlying bone structural data derived from X-ray scans. The correlation between underlying bony structure and outward superficial tissues is a correlation which is qualitatively and conceptually different than correlation or alignment between different scans of the same internal structure.
What is needed is some type of apparatus and methodology whereby multiple scanned cephalometric or dental images can be conveniently, economically and quickly combined for usefully correlated result.